Drilling apparatus



C. C. CHRISTIAN DB'ILLING APPARATUS Aug. 15, 41939.

Filed April lO, 193'? WU'M Patented Aug. l5, 1939 UNITED STATES PATENT OFFICE DRILLING APPARATUS cui c. cnramayictoria, rex.

Application April 10, 1937, Serial No. 136.049 2 Claims.' (Cl. Z55-61) This invention relates to drilling apparatus and has more particular relation to drilling apparatus equipped with means for ilushing out the "rat hole", or bottom o! the bore preparatory to making a test of the formation encountered. It is an object of the invention to provide the combination with a drill of means for controlling the discharge of the drilling, or ilushing, iluid into the bore.

It is another object of the invention to provide the combination with a ldrill of means whereby the passageways for the drilling iluid through the drill may be closed when it is desired to flush out the rat hole", and whereby the flushing iiuid maybe conducted on down beneath the drill and discharged into the rat hole", or the reduced lower end of the bore. In the process ci drilling wells when a. stratum, thought to contain oil has been reached, it is common practice to withdraw the drill stem and drill and replace the drill with one of areduced diameter and to lower the reduced drill backinto the bore for the purpose of reducing the ,bore and drilling on into the pay strata. This reduced bore is commonly known as a rat hole. This rat hole is usually of considerable depth. After the rat hole is formed it is sometimes desirable to withdraw the drill and replace it with one of a larger diameter, that is, having a diameter the same as that of the enlarged. bore above the "rat hole", for the purpose of reaming. the enlarged bore on down a distance. During this reaming process the rat hole" may become partly iilled with cuttings or very heavy drilling fluid so that it must be washed out or ilushed out preparatory to making a test. The apparatus herein described may be used during the reamingV process so that after the reaming is completed the rat hole may be washed out without,withdrawin'g the drill thus saving an extra trip.

With the above and other objects in view the' invention has particular relation to certain novel features of construction, arrangement of parts and use. an example o! whlchis given in this speciiication and illustrated inthe accompanying drawing, wherein:

Figure 1 shows a vertical sectional view of .a

drill showing the central bore closed so as to permit a discharge of the drillingnuld to the drill in the usual wa'y while carrying on ordinary drilling operations.

, yFigure 2j showsavside view o! the partly in section showing. assembled therewith, means for closing the drilling iluid channels of the drill and for.` conducting the drilling iiuid channels of beneath the drill.

the drill and for conducting a ushing fluid down intothe rat hole and Figure 3 showsan edge view thereof.

Referring now more particularly to the drawing wherein like numerals of reference designate 5 the same parts in each of the figures, 'the numeral I designates a drill, which, in the present instance is shown as ya drill of the iish tail type. The upper end of the drill is reduced and outwardly threaded to receive the lower end ot the drill collar 2 which forms a part of the drill stem extending to the ground surface and whereby the drill is driven. The drill ha's an axial bore 3 extending from the upper to the lower end thereof and in the present illustration there vis shown a pilot l around the bore and extending 'Ihe drill is provided with the channels 5, 5 for the discharge of the drilling iiuid on to the blades or cutters 6 o! the-drill. These channels lead downwardly and outwardly from the central bore 3 and beneath the upper ends of the channels the bore l is reduced in diameter forming an inside annular shoulder 1.

While carrying on the reaming operations as hereinabove described it is necessary that the bore 3 be closed and the channels 6 left open. For this purpose a plug 8 is dropped down through the drillstem into the drill and this plug has the enlarged head 9 at its upper endwhose outside diameter is approximately the same as that oi the inside diameter oi' the enlarged portion of the boi-e 3 and whose lower end'is shaped to conform to the shape of, and to tit on, the seat 'I -whereby the bore 3 will be closed to prevent the passage of the drilling fluid downwardly through the bore. When the head 9 is seated on the seat 1 its upper end will clear the upper ends of the `channels 5 so that the drilling'1 iluid will be forced to ilush out the cuttings from --the bottom of the bore.

The plug 8 -has an upstanding stem Il whose upper end carries a conical shaped head Il with which a conventional type of grapple may be engaged. This grapple is carried by the lower' I end oi' 'a cable in the usual way and may bek let down through the drill stem and engaged with the head il and the plug l withdrawn when it is desired to withdraw the same.

When the reaming operation has been completed the plug may be withdrawn and the flushing apparatus hereinafter described may' be lowered in its place. This ushing apparatus prises an elongated barrel I2 whose lower end is closed and provided with the reduced discharge outlets I3. The upper end of the barrel is reduced forming an external annular shoulder Il and surroundingV the reduced upper end of the barrel and resting on said shoulder there is a junk ring I on which is' located an expanslble sleeve II forming a packer. Screwed on to the upper end of the barrel there is a tubular cage I1 whose lower end abuts the upper end of the packer and whose upper end has the inlet openings Il. A stem Il upstands from the cage and is provided with a conical shaped head 2l with which the grappling tool hereinabove described may be engaged.

When the plug l has been removed the drill may be elevated and the flushing apparatus dropped down through the drill stem with the Junk ring I5 landed on the seat 1. In this position the lower end of the barrel will extend beneath the drill down into the rat hole as illustrated in Figure 2 and the packer I6 is of sutilcient length to close the upper end of the channels 5. A clean flushing fluid may then be forced down through the drill stem and it will pass inwardly through the openings I8 and down `through the tubular barrel I2 and out through .the outlet openings Il into the rat hole" and said ilushing iluid will return up around thedrill and drill stem thus flushing out all clogging ma.- terial from the "rat hole" preparatory to lowering a testing tool to test the formation pierced by the "rat hole. It may be stated that while flushing out the rat hole the pressure of the iluid against the upper end of the packer IE will cause the flexible packer to buckle and/orbend outwardly into sealing engagement with the drill passage thereby effectively closing the channels 5, during which buckling action of the ilexible sleeve the loosely mounted junk ring I5 follows the lower end of the latter upwardly and somewhat supports the same throughout the sealing operation. In

broad principle of theinvention will be definedby the appended claims.

What I claim is;

1. The combination with a drill having an axial bore extending from the upper to the lower end of the drill and having an inside seat around thebore, a discharge channel leading downwardly from the bore above said seat, of a tubular barrel shaped to ilt through the bore, annular means loosely mounted on said barrel to engage said seat, an expansible packing on said barrel and engaging said annular means, said packing and annular means being movable with respect to -said barrel whereby fluid pressure forces said packing to seal said channel.

2. In drilling apparatus, a drill having an axial bore whose lower end is reduced forming an inside upwardly facing seat, said drill having a channel leading downwardly from the bore above said seat, a tubular barrel having a ring thereon adapted to rest on said seat, said barrel being extended beneath the drill and formed into a nozzle having a lower end outlet, and an expansible sleeve 0n said barrel and seated on said ring, said ring and sleeve being'movable with respect to said barrel whereby said sleeve is'adapted to be expanded to close the upper end of said channel.

^ Y CARL C. CHRISTIAN. 

